Remove 100ms BLE command delay

test/models/message_reception_details_test.dart

@@ -2,6 +2,29 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:meshcore_sar_app/models/message_reception_details.dart';
 
 void main() {
+  test('drops impossible transmit estimate for received messages', () {
+    expect(
+      sanitizeEstimatedTransmitMs(
+        estimatedTransmitMs: 16 * 60 * 1000 + 54 * 1000,
+        senderToReceiptMs: 4200,
+      ),
+      isNull,
+    );
+  });
+
+  test(
+    'keeps close transmit estimate despite second-level timestamp rounding',
+    () {
+      expect(
+        sanitizeEstimatedTransmitMs(
+          estimatedTransmitMs: 1800,
+          senderToReceiptMs: 900,
+        ),
+        1800,
+      );
+    },
+  );
+
   test('round trips reception details json', () {
     final details = MessageReceptionDetails(
       capturedAt: DateTime.fromMillisecondsSinceEpoch(1700000000000),

test/providers/helpers/raw_session_retransmit_test.dart

@@ -47,9 +47,8 @@ void main() {
       expect(ok, isFalse);
     });
 
-    test('sends only requested indices and waits for ack', () async {
+    test('sends only requested indices', () async {
       final sent = <Uint8List>[];
-      final waited = <int>[];
       final ok = await serveCachedSessionFragments<_Fragment>(
         providerLabel: 'TestProvider',
         sessionId: 'deadbeef',
@@ -70,15 +69,6 @@ void main() {
             }) async {
               sent.add(payload);
             },
-        waitForFragmentAck:
-            ({
-              required sessionId,
-              required index,
-              timeout = const Duration(seconds: 8),
-            }) async {
-              waited.add(index);
-              return true;
-            },
         requestedIndices: {1, 2},
       );
 
@@ -86,37 +76,6 @@ void main() {
       expect(sent.length, equals(2));
       expect(sent[0], equals(Uint8List.fromList([20])));
       expect(sent[1], equals(Uint8List.fromList([30])));
-      expect(waited, equals([1, 2]));
-    });
-
-    test('fails when ack does not arrive', () async {
-      final ok = await serveCachedSessionFragments<_Fragment>(
-        providerLabel: 'TestProvider',
-        sessionId: 'deadbeef',
-        requester: _buildContact(outPathLen: 1),
-        fragments: [
-          _Fragment(0, Uint8List.fromList([1])),
-        ],
-        maxDirectPayloadHops: 3,
-        indexOf: (f) => f.index,
-        encodeBinary: (f) => f.payload,
-        sendRawPacket:
-            ({
-              required contactPath,
-              required contactPathLen,
-              required payload,
-            }) async {},
-        waitForFragmentAck:
-            ({
-              required sessionId,
-              required index,
-              timeout = const Duration(seconds: 8),
-            }) async {
-              return false;
-            },
-      );
-
-      expect(ok, isFalse);
     });
 
     test('fails when no requested index matches cached fragments', () async {